Capacitor

What I forgot to mention the Duelund are a great capacitors way too  much $$
and huge, they  are top notch caps great detail and depth ,just slightly better the the Jupiter in layering ,but the Jupiter Copper foil has great overall balance, and much less $$ ,they are within a % point or two of each other 
detail on top is very good on both  ,but the VH Audio CUTF  is the best of the best in that 
dept by adding between 2-3% in the VH as a bypass cap the best of both worlds
if you have  a capacitor you need 2 uf or under the VH audio are pretty neutral 
slightly to the warm side but very big and for a pr of 1 uf for example around $1k.
greatness  cost $$.

Jupiters will be here with me in 2 days can some one explain how many hours of burn in will open the cap and what should I expect in the sound  in the process of burn in to stay on track and not discard the caps

Prior to burn in, I generally hear what I'd describe as an uptight sound, lack of transparency, also, excessive attack , attenuated decay. I'm not going to generalize about tonality, timbre. For sure you'll know when they reach burned in state, often the change comes on in what seems an instant. Suddenly you'll hear an opening up, could also be called blooming of sound. I'm sure the burn in process is slow and ongoing, but almost without exception, the last bit happens in just an instant. Many say 100 hours is usual for the process, I hate to say any particular hours, expectation bias sets in with a set amount of hours. I'd say anywhere between 75 and 200 hours should get you most of the way there.
I usually don't even bother listening anymore prior to 75 hours or so, why suffer the burn in if you don't have to. You may be tempted to come to conclusions prior to burn in if you have to suffer through disappointing sound for too long. If new to cap swaps you may want to hear at least occasionally during burn in to evaluate before and after burn in sound.

Could there be an issue for the amp in any way?

Assuming he didn't change any values, no. I'd not go with less voltage rating than stock, and impedance values should stay stock or very close as they were chosen for a reason. Heat can be an issue for some film caps, certain materials such as paper, bees wax may not be best for high heat environment. Physical size could be issue, rubbing components together could be issue.