Welcome! I cannot answer your question but I know that other members will.

If they want to play football I would say a Polytunnel would be better than a glass greenhouse. Steve does well with his.

glass is best but as said horses for courses . know budding footballers excuse the pun . welcome bye the way .

glass doesn't go dull after 5-10 yrs but as the boys are small then polycarb might be best. I have glass and I have 2 girls. but the greenhouse was sited away from their main play area.