need shaft input, wanting to get new irons

i currently have a set of older mizuno's, mx-25. these were fitted for me years ago and have rifle 5.0, non flighted. are 5.0 considered a reg or reg+ ?  i like these clubs/shafts and play well with them, i just want to get a new set. particular jpx 825pro.   a email response from mizuno informed me that my ole mx-25 are like inbetween the 825 and 825pro and sugested to go with 825pro based on what i like in a clubhead, also that these are for 6-18 handicap spectrum. i have no idea what my handicap is,  but breaking 80 is more often than it is not.   the 825pro are not offered with rifle shafts. mizuno fitting gave me 3 shaft recomendations, dg r300, project x 5.0 , kbs tour - reg .   now i like the feel and flight of my rifles.  im kinda not wanting dg, and is a toss up from project x and kbs tour. both of these shafts are a little lighter than my rifles. so im looking for some input from those of you that have some experience in these shafts, rifle-projext x - kbs tour. while using a online fitting at rifle it suggsted 5.5 and dg s300, kbs suggested reg , but then there is 5.0-5.5 and reg and reg+, how big a difference are inbetween these flexes. it seems like im right on the borderline? ive already had the experience of getting to stiff a shaft which in turn i could hit the clubs with a darn, which brought me to my rifle 5.0 .  i also find hitting indoors, it just isnt the same, seems i dont connect as well . my local golf store which in turn has launch monitors and various brands fitting carts, but to tell you the truth i dont trust at all in a custom fitting. which would turn me to travel a few hrs to visit a golfsmith store or golf galaxcy. so any input any of you can give me is greatly appreciated which in turn i hope i can make a shaft selection then . thanks

also i will be getting new wedges, whats the take on the shafts in the wedges?  get same as irons or is the "wedge flex" ok ?

I build my own clubs as you can tell by my profile... Rifle shafts are typically 5.0 for regular flex 5.5 regular Plus 6.0 for stiff and so on.... I have tried all of your shaft options but there is another option that you may have not considered actually two... True Temper black gold and tt lite xl... Project x shafts are great considering you shoot around 80... But that's around e what I shoot... And I play stiff flex... But I wouldn't know cause I may swing a lot faster than you esop I can't make a judgment on flex unless I saw you swing the club... TOn wedges to answer that qiestion it shouldn't be a problem with wedge flex because in my experience wedge flex is like a soft stiff flex so I would say that it would fall between your 5.5 and 6.0... But it's up to you this is just my honest opinion... Hope you hit them solid whatever you decide to do.

power aid ,

Here's chart courtesy of GolfWRX.com that compares different shafts on FCM, frequency coefficient matching. This system allows comparison of different shaft makes and models for stiffness. One problem golfdom has is the lack of an industry standard for shaft stiffness. Some S shafts are softer than others... the chart allows systematic comparison using each shaft's FCM rating.

For example, a Project X 5.0 has FCM = 5.5, whereas a DG R300 has FCM = 4.8

Both of these are ranked as regular shafts by the manufacturer, but the PX is .7 a flex stiffer than the DG. The DG, however is about 12 grams heavier.