I have a Hoyt dorado (50# @ 28") that should be here, next week.

I have a friend who has some CX 250's cut to 29.5" that says I can use them to see if they'll work with my bow. Total arrow weight is 535gr. utilizing a 125gr. tip (and the std. CX insert).

If the spine is too stiff (expected), I don't necessarily want to go up in tip weight, due to it bringing my overall arrow weight up too high.

Is it a safe assumption....that I should just order 150's....if these exact arrows don't fly right?  My assumption is I could easily add weight tubes to get my total arrow weight up....and that I'd probably be able to utilize all of my 125gr BH's with these shafts "at some length".  If I get too stiff of a spine reaction, I could also either leave the 150 shafts a little long OR switch to 100GR BH's.

Is my "logic" sound?

i would try before you buy. that bow is probably cut past centre. you might need a stiffer arrow than expected. in my experience there's nothing surer than getting burned when trying to anticipate what will work.

I AM trying the 250's before I buy.  That's the beauty of it.

Upping the weight won't make your arrows too heavy.

50# bow....and I'm always reading that 10gr total arrow weight/# of DW is a good "std" for hunting and targets.

Is this bad info?

Jeff, 10gr per pound is a starting point, I personally wouldn't go any lower, higher never hurts! I shoot a 620+ grain arrow out of 50# bows and they pack a punch! I was shooting a 789gr arrow out of a 55# bow today and I tell ya, what an arrow and the bow wasn't to shabby either!

Total arrow weight is a personal choice.I don't like an arrow that will drop like a rock at longer distance.Your 10 grains per pound is plenty for deer.More weight will always penetrate better.You just have to decide what works best for you.

If the arrow is too stiff,a longer shaft or more point weight will weaken the spine.